Introduction
The Tyrer-Cuzick model, also called the IBIS tool, is one of the most trusted ways to estimate a woman's chance of getting breast cancer. Doctors and clinics use it to decide if a patient needs extra screening, such as an MRI, or medicines that can help lower risk. The model looks at many parts of your health, including your age, weight, family history, hormone use, breast density, and whether you carry a BRCA gene mutation. It then combines all of these factors to give you a 10-year risk and a lifetime risk score.
This calculator uses a simplified version of that model. It applies known risk factors and multiplies them together to produce an estimate. It is not the validated clinical Tyrer-Cuzick/IBIS software and may give results that differ from the official tool. You should not use the numbers from this page to make medical decisions on your own. Instead, share your results with your doctor or visit a breast cancer risk clinic for a full assessment.
To get started, fill in each section below with your personal and family health details, then press Calculate. The tool will show your estimated risk, compare it to the average woman your age, and explain each step of the math behind your score.
How to Use Our Tyrer-Cuzick Calculator
Enter your personal health details, family history, and reproductive history below. The calculator will estimate your 10-year and lifetime breast cancer risk and compare it to the average woman your age.
Current Age: Enter your age in years. This tool works for ages 18 to 90. Use the plus and minus buttons or type your age directly.
Unit System: Choose Imperial (feet, inches, pounds) or Metric (meters, kilograms). The calculator will convert your numbers if you switch between the two.
Height and Weight: Enter your height and weight using your chosen unit system. The calculator uses these to find your BMI, which can affect breast cancer risk after menopause.
Have You Ever Had a Menstrual Period: Select Yes or No. If Yes, enter the age when your first period started. Leave the age blank if you do not remember.
Have You Given Birth to a Live Child: Select Yes, No, or Unknown. If Yes, enter your age when your first child was born. Leave the age blank if you do not remember.
Menopause Status: Select whether you are premenopausal, perimenopausal, postmenopausal, or unsure. If you are postmenopausal, enter the age when menopause began.
Hormone Replacement Therapy (HRT): Select whether you have never used HRT, stopped it 5 or more years ago, stopped it less than 5 years ago, or currently use it. If you recently stopped or currently use HRT, choose whether it is estrogen-only, combined, or unknown.
Prior Breast Biopsy: Select whether you have had no biopsy, a biopsy with unknown results, or a biopsy that showed hyperplasia without atypia. Check the box for atypical hyperplasia if abnormal but non-cancerous cells were found. Check the box for LCIS if lobular carcinoma in situ was found.
Breast Density: Choose how your breast density was measured. If you know your BI-RADS category (A through D), select it. If you have a density percentage from a VAS or Volpara report, enter that number. Choose Unknown if you have not had this measured.
Personal Ovarian Cancer History: Select Yes if you have been diagnosed with ovarian cancer. Otherwise select No.
Ashkenazi Jewish Heritage: Select Yes, No, or I don't know. This heritage is linked to higher rates of certain gene mutations that raise breast cancer risk.
BRCA Mutation Status: Select whether you have not been tested, tested negative, or tested positive for BRCA1 or BRCA2. These are inherited gene changes that strongly raise breast cancer risk.
Personal Breast Cancer Diagnosis: Select Yes if you have been diagnosed with breast cancer. This model is not designed for people with a prior diagnosis, so results should be read with caution.
First-Degree Relatives with Breast Cancer: Enter the number of mothers, sisters, or daughters who have had breast cancer. Enter 0 if none.
Second-Degree Relatives with Breast Cancer: Enter the number of grandmothers, aunts, half-sisters, nieces, or cousins who have had breast cancer. Enter 0 if none.
Additional Family Details: Check any boxes that apply: a relative diagnosed before age 50, a relative with cancer in both breasts, a relative with ovarian cancer, or a male relative with breast cancer. These details help refine your family history risk.
Calculate Button: Press "Calculate" to see your results. The tool will show your estimated 10-year risk, lifetime risk to age 85, chance of staying breast-cancer free, and a risk category. A bar chart and gauge chart will also appear to help you compare your risk to the average.
What Is the Tyrer-Cuzick Breast Cancer Risk Calculator?
The Tyrer-Cuzick model, also called the IBIS tool, is a way to estimate a woman's chance of getting breast cancer. It was published in 2004 by Jonathan Tyrer, Stephen Duffy and Jack Cuzick, combining the BRCA genes, a low-penetrance gene and personal risk factors: a woman's family history is run through Bayes' theorem to estimate the chance she carries a predisposing gene, and that likelihood is refined by her personal history.1 Unlike simpler models, it looks at a wide range of factors, including family history, hormones, body size, breast density, and genetics, to give a more complete picture of risk.
How Does It Work?
The calculator takes information you enter about your health and background. It then compares your risk factors against data from large studies of women over many years. The result is two main numbers: your 10-year risk (your chance of getting breast cancer in the next 10 years) and your lifetime risk (your chance from now until age 85). It also shows you how your numbers compare to an average woman of the same age.
What Factors Affect Your Risk?
Many things can raise or lower breast cancer risk. The main ones this tool considers are:
- Age: Risk goes up as you get older.
- Family history: Having a mother, sister, or daughter with breast cancer raises your risk. The more relatives affected, the higher the risk.
- BRCA1 and BRCA2 genes: These inherited gene changes greatly increase the chance of breast cancer.
- Breast density: Dense breast tissue makes cancer harder to spot and raises risk.
- Hormone history: Starting periods early, going through menopause late, or using hormone replacement therapy (HRT) can increase risk.
- Body weight: A higher BMI after menopause is linked to higher risk.
- Atypical hyperplasia or LCIS: These are abnormal cell changes found on a breast biopsy. They are not cancer, but they are strong risk markers.
What Do the Results Mean?
The American Cancer Society recommends against MRI screening at a lifetime risk under 15% and recommends annual MRI alongside mammography from approximately 20 to 25% or greater, as estimated by models largely dependent on family history.2 A risk of 30% or more is labelled high here, where your doctor may discuss ways to lower it, such as medication or closer monitoring.
The tool also shows your chance of staying breast-cancer free over the next 10 years. For most women, this number is above 90%, which can be reassuring.
Important Limitations
This online version uses a simplified model. It is not the same as a clinical Tyrer-Cuzick/IBIS assessment run by a doctor or genetic counselor. The real tool uses a detailed family tree (pedigree) and more complex math. Results from this page may differ from a clinical score. Do not use this tool to make medical decisions. Always talk to a healthcare professional about your personal breast cancer risk and what screening plan is right for you. Taking care of your overall health (monitoring your calorie intake, staying physically active, and keeping a healthy BMI) can also play a role in reducing your risk.